1. Field of the Invention
The present invention relates to an apparatus and method for navigating a vehicle to a destination to which a vehicle occupant desires to reach using a display unit.
2. Description of Background Art
Various types of vehicular navigating systems (also called, vehicular route guidance apparatuses) in which an optimum route of travel from a start point of the vehicle to a destination is searched and derived and both of the optimum route and a present position of the vehicle are displayed on a display screen of a display unit have been proposed.
FIG. 1A exemplifies a displayed image in a case of one of the previously proposed vehicular navigating systems.
As shown in FIG. 1A, the present position of the vehicle is superimposed and displayed on the display image screen with an arrow mark and with its surrounding portion of the arrow marked present position encircled by a dotted line. Then, when an operator operates a predetermined switch, a range encircled with the dotted line is displayed in an extended form as shown in FIG. 1B. This permits the operator to recognize a road (traffic) situation surrounding the present position in details. In this way, when the displayed images are exchanged from FIG. 1A to FIG. 1B and vice versa, it is always necessary to operate the predetermined switch. This makes the operation troublesome.
On the other hand, another previously proposed navigating system in which road maps having different reduction of scales are simultaneously displayed on the display image screen, this display form being, so-called, superimposed displayed patterns, as shown in FIG. 2.
FIG. 2 exemplifies the displayed image screen of the other previously proposed vehicular navigating system, with intersection situations surrounding the present position of the vehicle being displayed in the extended scale form on a right upper corner of the displayed image screen. This other previously proposed navigating system permits the vehicular occupant to recognize the road map having a wide range of view with the present position of the vehicle as a center and to recognize the road (traffic) situation surrounding the present position of the vehicle in details.
However, since, in the displayed image screen shown in FIG. 2, the part of the road map has been displayed on the right upper corner of the displayed image screen in the extended scale form, the actual road map to be displayed on the right upper corner of the displayed image screen cannot be viewed from the displayed image screen (is hidden by the extended part of the road map). Hence, in a case where, for example, the vehicle driver tries to turn a right corner corresponding to the displayed portion of the hidden part (not displayed), the vehicle driver cannot recognize a road (traffic) situation in the forward direction. This makes the vehicle driver inconvenient.